1. Field of the Invention
The present invention generally relates to a method and apparatus for controlling screen brightness of a user device, and more particularly, to a method and apparatus for controlling screen brightness according to an illumination change capable of automatically controlling screen brightness based on an environment illumination.
2. Description of the Related Art
Various devices capable of communicating and processing personal information while moving, such as a mobile communication terminal, a such as a Personal Digital Assistant (PDA), an electronic organizer, a smartphone, and a tablet Personal Computer (PC) have been introduced during the recent advancement of digital technologies. Such user devices have been made to include various functions such as calling including voice and video, message transmission and reception including a Short Message Service (SMS)/Multimedia Message Service (MMS) and e-mail, navigation, photographing, broadcast replay, media (moving image and music) replay, Internet, messenger, and Social Network Service (SNS) functions.
Screen brightness in user devices is set according to a user's selection, and is maintained until the brightness is changed by user's operation. That is, the screen brightness of the display unit is constantly maintained regardless of the surrounding environment. Hence, when the user is in a dark environment, the screen is displayed well, but when goes to a bright environment, the screen may not be displayed well. In contrast, the screen is displayed well in a bright environment, but the screen becomes too bright in a dark environment, causing the user's eyes to become tired.
In order to solve this problem, an automatic brightness control function using an illumination sensor mounted on a user device has recently been provided. That is, the visibility of the screen displayed through the display unit changes according to the environment illumination and the screen brightness. For example, for the screen of the same brightness, the user may feel bright in a dark place, but dark in a bright place. Hence, the automatic brightness value setting of the screen in a user device applies screen brightness according to the illumination using the illumination sensor. The screen is controlled to be bright in a bright environment and to be dark in a dark environment using the illumination sensor.
However, the conventional art leads to the following inconveniences, which are not considered when automatically changing the screen brightness according to the environment illumination. That is, when the screen brightness is regulated, the illumination environment in which the screen brightness is to be changed is not considered. Hence, if the screen brightness is frequently changed whenever the illumination is changed, the user's screen concentration decreases, which decreases usability.
Further, an exceptional situation that the illumination sensor is covered by a user's body part, such as a hand or a face, or an object such as a noise-type illumination change, is not considered. That is, the screen brightness is changed when user covers the illumination sensor.
In addition, visually adapting to illumination when moving from a dark place to a bright place is different from visually adapting to darkness when moving from a bright place to a dark place. However, the conventional function of controlling screen brightness according to illumination does not consider characteristics of a user's angle of vision, such as light adaptation and dark adaptation.